The present invention relates to a firearm barrel having components made of different materials, in which a protective sleeve is disposed between a rifled metal insert and an exterior light weight material.
Firearm manufacturers have desired to manufacture light weight firearm barrels for some time. Such light weight barrels are desired, especially in connection with firearms that will be used for target shooting, especially when the firearm will be held for long periods of time. In addition, light weight barrels are desired for firearms that will be carried into the field for hunting.
One approach to manufacture a light weight firearm barrel has involved the use of a rifled liner, or metal insert, wrapped in a protective material. Rifled liners are long metal inserts which are used to refurbish traditional metal rifle barrels in which the interior of the barrel has been damaged or worn over time. The rifled liners are thin and very susceptible to bending. One method to make a light weight firearm barrel has been to hand wrap the rifled liner with fiberglass such as ACCULIGHT™. The fiberglass is then ground to produce a smooth surfaced firearm barrel. This method, while producing a light weight firearm barrel, is very labor intensive and, accordingly, very expensive. Additionally, because the rifled liner is very susceptible to bending, great care must be taken in connection with wrapping the fiberglass around the rifled liner so as to maintain the alignment and, hence, shooting accuracy of the firearm barrel.
Yet another method that has been used to create light weight firearm barrels involves injection molding plastic material around a rifled liner. Such a process is shown in Chestnut, et al., U.S. Pat. No. 4,769,938. In this firearm barrel, the barrel includes a casing of plastic material that is located about the majority of the length of the rifled liner and extends throughout the length of the firearm barrel. In forming the plastic casing, the rifled liner (or metal insert) is supported in injection molding equipment that permits the injection molding of plastic to a desired diameter around portions of the rifled liner and other barrel components. The problem with injection molding plastic material around a rifled liner is that the heat and pressure used in connection with the injection molding process warps the rifled liner. Firearm barrels produced in this fashion therefore tend to exhibit poor shooting accuracy.
Accordingly, what is therefore desired is a light weight firearm barrel which is easily and inexpensively made and which exhibits good shooting accuracy.